Toner binder and toner

Abstract

To provide a toner binder with which a toner excellent in durability and electrification characteristics and having a wide fixing width can be obtained.SOLUTION: A toner binder includes polyester resin obtained through polycondensation of an alcohol component and a carboxylic acid component. The polyester resin is polyester resin (A) in which the alcohol component includes ethylene glycol and the carboxylic acid component includes terephthalic acid, and in measurement using fluorescent X-rays, includes barium elements within a range of 10-1500 ppm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner binder and a toner. [Background technology]

[0002] In recent years, advances in electrophotography have led to efforts to expand the application of electrophotography to commercial and industrial printing. Commercial and industrial printing require stable, high-speed printing, which requires a certain level of low-temperature fixability and hot offset resistance, i.e., a wide fixation range. Other requirements include durability against shear and compression caused by agitation within the toner cartridge to prevent the generation of fine powder, and maintaining charging performance to enable stable mass printing of images of the same quality. The toner binder has a significant effect on the toner characteristics as described above, and known examples include polystyrene resin, styrene-acrylic resin, polyester resin, epoxy resin, polyurethane resin, and polyamide resin. However, polyester resin has attracted particular attention because it is easy to achieve a balance between fixability and chargeability. For example, a toner binder that has excellent fixing and charging properties and contains a polyester resin containing an aliphatic diol having 2 to 4 carbon atoms as a main component has been disclosed (Patent Documents 1 and 2). However, it cannot be said that the toner has sufficient durability, chargeability, and fixing width to be used in commercial printing and industrial printing, and improvements in these areas are desired. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-141966 [Patent Document 2] Japanese Patent Application Publication No. 9-278873 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a toner binder that can provide a toner having excellent durability and chargeability and a wide fixing width. [Means for solving the problem]

[0005] The present inventors have conducted extensive research and have arrived at the present invention. That is, the present invention is a toner binder containing a polyester resin obtained by polycondensation of an alcohol component and a carboxylic acid component, wherein the alcohol component is ethylene glycol. and trimethylolpropane The carboxylic acid component is a polyester resin (A) containing terephthalic acid, and the barium element is contained in a range of 10 to 1500 ppm when measured by fluorescent X-ray. It contains calcium in the range of 20 to 3000 ppm and phosphorus in the range of 2 to 500 ppm. The toner binder is characterized by comprising: [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a toner binder that is excellent in durability and chargeability and that can give a toner having a wide fixing width. DETAILED DESCRIPTION OF THE INVENTION

[0007] The toner binder of the present invention is a toner binder containing a polyester resin obtained by polycondensing an alcohol component and a carboxylic acid component, wherein the polyester resin is a polyester resin (A) in which the alcohol component contains ethylene glycol and the carboxylic acid component contains terephthalic acid, and is characterized in that the polyester resin contains barium element in a range of 10 to 1500 ppm as measured by fluorescent X-rays. The toner binder of the present invention will be described below in order.

[0008] The toner binder of the present invention contains a polyester resin obtained by polycondensing an alcohol component and a carboxylic acid component. The polyester resin in this specification may be a polyester resin (A) in which the alcohol component contains ethylene glycol and the carboxylic acid component contains terephthalic acid, or a polyester resin (B) other than the polyester resin (A).

[0009] First, the polyester resin (A) will be described. The polyester resin (A) contains ethylene glycol as an alcohol component and terephthalic acid as a carboxylic acid component.

[0010] When the carboxylic acid component contains terephthalic acid, the durability of the toner can be improved and the chargeability can be improved.

[0011] The polyester resin (A) may contain a polyol component (x) in addition to ethylene glycol. The polyol component (x) includes a diol (x1) other than ethylene glycol and a trihydric or higher polyol (x2), which may be used alone or in combination of two or more.

[0012] Examples of the diol (x1) include alkylene glycols having 3 to 36 carbon atoms (propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol), alkylene ether glycols having 4 to 36 carbon atoms (diethylene glycol, triethylene glycol, dipropylene glycol, Examples of the alkylene oxide adduct include alkylene glycols, cycloaliphatic diols having 6 to 36 carbon atoms (e.g., 1,4-cyclohexanedimethanol and hydrogenated bisphenol A), (poly)alkylene oxide adducts of the above-mentioned cycloaliphatic diols (preferably having an average number of moles added of 1 to 30), and aromatic diols [monocyclic dihydric phenols (e.g., hydroquinone) and bisphenols] and alkylene oxide adducts of the above-mentioned aromatic diols (preferably having an average number of moles added of 2 to 30).

[0013] The alkylene oxide adduct of bisphenol can be obtained by adding alkylene oxide (hereinafter, "alkylene oxide" may be abbreviated as AO) to bisphenol.

[0014] Examples of bisphenols include those represented by the following general formula (1). HO-Ar-P-Ar-OH (1) [In the formula, P represents an alkylene group having 1 to 3 carbon atoms, -SO2-, -O-, -S-, or a direct bond, and Ar represents a phenylene group in which a hydrogen atom may be substituted with a halogen atom or an alkyl group having 1 to 30 carbon atoms.]

[0015] Specific examples of bisphenols include bisphenol A, bisphenol F, bisphenol B, bisphenol AD, bisphenol S, trichlorobisphenol A, tetrachlorobisphenol A, dibromobisphenol F, 2-methylbisphenol A, 2,6-dimethylbisphenol A, and 2,2′-diethylbisphenol F, and two or more of these can also be used in combination.

[0016] Examples of the alkylene oxide to be added to the bisphenol include alkylene oxides having 2 to 30 carbon atoms, such as ethylene oxide (hereinafter, "ethylene oxide" may be abbreviated as EO), propylene oxide (hereinafter, "propylene oxide" may be abbreviated as PO), butylene oxide, tetrahydrofuran, and combinations of two or more of these.

[0017] Of these diols (x1), from the viewpoints of low-temperature fixability and heat-resistant storage stability, alkylene glycols having 3 to 36 carbon atoms and alkylene oxide adducts of aromatic diols are preferred, alkylene glycols having 3 to 10 carbon atoms and alkylene oxide adducts of bisphenols (average number of added moles is preferably 2 to 5) are more preferred, alkylene glycols having 3 to 6 carbon atoms and alkylene oxide adducts of bisphenol A (average number of added moles is preferably 2 to 5) are even more preferred, and EO and / or PO adducts of bisphenol A (average number of added moles is preferably 2 to 3) are particularly preferred.

[0018] The alcohol component of the polyester resin (A) preferably contains an alkylene oxide adduct of bisphenol A, and more preferably contains an EO and / or PO adduct of bisphenol A (the average number of moles added is preferably 2 to 3). When the alcohol component of the polyester resin (A) contains an alkylene oxide adduct of bisphenol A, the durability of the toner state is improved compared to when this adduct is not contained.

[0019] Examples of the tri- or higher hydric polyol (x2) include aliphatic polyhydric alcohols having 3 to 36 carbon atoms and having a valence of 3 or more, sugars and derivatives thereof, alkylene oxide adducts of aliphatic polyhydric alcohols (the average number of moles added is preferably 1 to 30), alkylene oxide adducts of trisphenols (trisphenol PA, etc.) (the average number of moles added is preferably 2 to 30), and alkylene oxide adducts of novolak resins (including phenol novolak and cresol novolak, etc., having an average degree of polymerization of preferably 3 to 60) (the average number of moles added is preferably 2 to 30).

[0020] Examples of the aliphatic polyhydric alcohol having 3 to 36 carbon atoms and a valence of 3 or more include alkane polyols and their intramolecular or intermolecular dehydration products, such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, sorbitan, polyglycerin, and dipentaerythritol. Furthermore, examples of sugars and their derivatives include sucrose and methyl glucoside.

[0021] Among these trivalent or higher polyols (x2), from the viewpoint of achieving both low-temperature fixability and hot offset resistance, preferred are trivalent or higher aliphatic polyols having 3 to 36 carbon atoms, and alkylene oxide adducts (average number of added moles is preferably 2 to 30) of novolak resins (including phenol novolak and cresol novolak, etc., with an average degree of polymerization preferably of 3 to 60), more preferred are trivalent aliphatic polyols having 3 to 8 carbon atoms, and particularly preferred is trimethylolpropane.

[0022] The diol (x1) in the polyol component (x) of the polyester resin (A) is preferably 80 to 100 mol %. When the diol (x1) and the trihydric or higher polyol (x2) are used in combination, the molar ratio of the diol (x1) to the trihydric or higher polyol (x2) [(x1) / (x2)] is preferably 80 / 20 to 99 / 1, more preferably 85 / 15 to 98 / 2, from the viewpoint of hot offset resistance.

[0023] Furthermore, the alcohol component of the polyester resin (A) may contain a monool component in addition to the polyol component (x), if necessary. Examples of the monool include linear or branched alkyl alcohols having 1 to 30 carbon atoms (e.g., methanol, ethanol, isopropanol, 1-decanol, dodecyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, and lignoceryl alcohol).

[0024] Of these monools, from the viewpoints of image strength and heat-resistant storage stability, linear or branched alkyl alcohols having 8 to 24 carbon atoms are preferred, linear alkyl alcohols having 8 to 24 carbon atoms are more preferred, and dodecyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, and lignoceryl alcohol are even more preferred.

[0025] The polyester resin (A) may contain a polycarboxylic acid component (y) in addition to terephthalic acid. Examples of the polycarboxylic acid component (y) include dicarboxylic acids (y1) other than terephthalic acid and trivalent or higher polycarboxylic acids (y2), which may be used alone or in combination of two or more.

[0026] Examples of dicarboxylic acids (y1) include aromatic dicarboxylic acids having 8 to 36 carbon atoms (such as isophthalic acid and naphthalenedicarboxylic acid), aliphatic dicarboxylic acids having 2 to 50 carbon atoms (such as oxalic acid, malonic acid, succinic acid, adipic acid, lepargic acid, and sebacic acid), alicyclic dicarboxylic acids having 6 to 40 carbon atoms (such as dimer acids (dimerized linoleic acid)), alkene dicarboxylic acids having 4 to 36 carbon atoms (such as alkenylsuccinic acids such as dodecenylsuccinic acid, maleic acid, fumaric acid, citraconic acid, and mesaconic acid), and ester-forming derivatives thereof. Here, the term "ester-forming derivatives" refers to carboxylic acid anhydrides, alkyl (such as methyl, ethyl, butyl, and stearyl having 1 to 24 carbon atoms, preferably those having 1 to 4 carbon atoms) esters, and partial alkyl esters.

[0027] Among these dicarboxylic acids (y1), from the viewpoint of achieving both low-temperature fixability, hot offset resistance, and heat-resistant storage stability, aromatic dicarboxylic acids having 8 to 36 carbon atoms, aliphatic dicarboxylic acids having 2 to 50 carbon atoms, and alkene dicarboxylic acids having 4 to 36 carbon atoms are preferred, and isophthalic acid, adipic acid, succinic acid, maleic acid, and fumaric acid are more preferred, isophthalic acid, adipic acid, fumaric acid, and succinic acid are even more preferred, and isophthalic acid, adipic acid, and succinic acid are particularly preferred. Furthermore, anhydrides or lower alkyl esters of these acids may also be used.

[0028] Examples of the trivalent or higher polycarboxylic acid (y2) include trivalent or higher aromatic polycarboxylic acids having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, etc.), aliphatic (including alicyclic) tricarboxylic acids having 6 to 36 carbon atoms (hexanetricarboxylic acid, decanetricarboxylic acid, etc.), and ester-forming derivatives thereof.

[0029] Among these trivalent or higher polycarboxylic acids (y2), aromatic polycarboxylic acids having 9 to 20 carbon atoms are preferred, and trimellitic acid and pyromellitic acid are more preferred, from the viewpoint of achieving both low-temperature fixability and hot offset resistance. Furthermore, anhydrides or lower alkyl esters of these acids may also be used.

[0030] Furthermore, the carboxylic acid component of the polyester resin (A) may contain a monocarboxylic acid component, if necessary. Examples of the monocarboxylic acid include aromatic monocarboxylic acids having 7 to 37 carbon atoms (such as benzoic acid, toluic acid, 4-ethylbenzoic acid, and 4-propylbenzoic acid), and aliphatic (including alicyclic) monocarboxylic acids having 2 to 50 carbon atoms (such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, and behenic acid).

[0031] Of these monocarboxylic acids, aromatic monocarboxylic acids having 7 to 37 carbon atoms are preferred, and benzoic acid is more preferred, from the viewpoint of image strength and heat-resistant storage stability.

[0032] The polyester resin (A) preferably contains barium element in the range of 10 to 1500 ppm based on the weight of the polyester resin (A) as measured by fluorescent X-rays. The content of barium element contained in the polyester resin (A) can be determined by adjusting the amount of the barium element-containing compound added during the production of the polyester resin (A). In this specification, the quantitative determination of the barium element content by fluorescent X-rays will be described below. <Sample preparation> A pressure molding method can be used, in which powders such as polyester resin (A), toner binder, and toner are compressed into pellets. For example, a powder sample can be filled into the center of a 5 mm thick ring made of polyvinyl chloride resin to form a light mound, and then pressed into pellets using a press with a load of 10 tonnes. Care must be taken to avoid contamination with other components, especially barium element. In particular, in the case of toner, barium element may be contained in the external additives, so the toner must first be ultrasonically cleaned with methanol or the like to remove the external additives from the surface, and then surface analysis such as STEM must be performed to confirm that the external additives have been removed. This allows for accurate measurement of the barium element content. <Measurement method> It is possible to prepare a calibration curve using a standard sample whose barium element concentration is known in advance and determine the analytical value from the X-ray intensity of the analytical sample, or, if the composition of most resins is known, to obtain an approximate content using the fundamental parameter method (FP method). However, except in cases where the contents of toner, etc., are unknown, the FP method is relatively less accurate, so it is preferable to use the calibration curve method, which can measure the barium element concentration more accurately. <Measuring equipment> For example, it can be measured using an X-ray fluorescence analyzer (Rigaku Corporation, Supermini200) or the like.

[0033] The polyester resin (A) preferably contains calcium element in the range of 20 to 3000 ppm based on the weight of the polyester resin (A) as measured by fluorescent X-rays. The content of calcium element contained in the polyester resin (A) can be determined by adjusting the amount of the calcium element-containing compound added during the production of the polyester resin (A). In this specification, the content of calcium element can be determined by fluorescent X-rays in the same manner as the content of barium element.

[0034] The polyester resin (A) preferably contains phosphorus element in the range of 2 to 500 ppm based on the weight of the polyester resin (A) as measured by fluorescent X-rays. The content of phosphorus contained in the polyester resin (A) can be determined by adjusting the amount of the phosphorus-containing compound added during the production of the polyester resin (A). In this specification, the content of phosphorus element can be determined by fluorescent X-rays in the same manner as the content of barium element.

[0035] The acid value of the polyester resin (A) is preferably from 0 to 50 mgKOH / g, more preferably from 0.1 to 30 mgKOH / g, from the viewpoints of low-temperature fixability, charge retention rate, and durability of print quality. The acid value can be measured by the method specified in JIS K0070.

[0036] The glass transition temperature of the polyester resin (A) is preferably from 50 to 75°C, more preferably from 55 to 70°C, from the viewpoint of heat-resistant storage stability and low-temperature fixability. The glass transition temperature (Tg) of the polyester resin (A) can be determined by the method (DSC method) specified in ASTM D3418-82. For measuring the glass transition temperature (Tg), for example, a DSC Q20 manufactured by TA Instruments can be used. The glass transition temperature (Tg) can be measured under the following conditions. <Measurement conditions> (1) Heat from 30°C to 150°C at 20°C / min (2) Hold at 150°C for 10 minutes (3) Cool to -35°C at 20°C / min (4) Keep at -35°C for 10 minutes (5) Heat up to 150°C at 20°C / min (6) The differential scanning calorimetry curve measured in the step (5) is analyzed, and the position of the inflection point is determined as the glass transition temperature.

[0037] The weight average molecular weight of the polyester resin (A) is preferably from 3,000 to 100,000, more preferably from 5,000 to 50,000, from the viewpoints of low-temperature fixability and toner durability.

[0038] In the present invention, the weight average molecular weight and the peak top molecular weight can be measured using gel permeation chromatography (GPC) under the following conditions. Device (example): Tosoh Corporation HLC-8120 Column (example): 2 TSK GEL GMH6 [Tosoh Corporation] Measurement temperature: 40℃ Sample solution: 0.25 wt% THF solution Solution injection volume: 100μL Detector: Refractive index detector Standard substance: 12 standard polystyrenes (TSK standard POLYSTYRENE) manufactured by Tosoh Corporation (molecular weight: 500, 1,050, 2,800, 5,970, 9,100, 18,100, 37,900, 96,400, 190,000, 355,000, 1,090,000, 2,890,000) For measuring the molecular weight, a sample is dissolved in tetrahydrofuran (THF) to a concentration of 0.25% by weight, and the insoluble matter is filtered off using a PTFE filter with an aperture of 220 nm to obtain a sample solution.

[0039] Of the alcohol components, the content of ethylene glycol is preferably 10 to 60 mol %, more preferably 20 to 50 mol %, based on the total number of moles of the alcohol components, from the viewpoint of chargeability (charge retention rate). In the alcohol component, the content of the alkylene oxide adduct of bisphenol A is preferably 0 to 70 mol %, more preferably 0 to 60 mol %, based on the total number of moles of the alcohol component, from the viewpoint of durability. Of the alcohol components, the content of alcohol components other than ethylene glycol and alkylene oxide adducts of bisphenol A is preferably 0 to 70 mol %, and more preferably 0 to 60 mol %, based on the total number of moles of the alcohol components, from the viewpoint of chargeability (charge retention rate).

[0040] Of the carboxylic acid components, the content of terephthalic acid is preferably 30 to 100 mol %, more preferably 40 to 100 mol %, based on the total number of moles of the carboxylic acid components, from the viewpoint of durability of the toner. Of the carboxylic acid components, the content of carboxylic acid components other than terephthalic acid is 0 to 70 mol %, preferably 0 to 60 mol %, based on the total number of moles of the carboxylic acid components, from the viewpoint of durability of the toner.

[0041] The reaction ratio of the alcohol component to the carboxylic acid component, expressed as the molar ratio of hydroxyl groups to carboxyl groups {[OH] / [COOH]}, is preferably 1 / 2 to 2 / 1, more preferably 1 / 1.3 to 1.5 / 1, and even more preferably 1 / 1.2 to 1.4 / 1.

[0042] The polyester resin (A) can be obtained by mixing an alcohol component containing ethylene glycol with a carboxylic acid component containing terephthalic acid, and carrying out a polycondensation reaction in the presence of a polymerization catalyst. The terephthalic acid component contained in the polyester resin (A) may be a terephthalic acid component derived from PET (polyethylene terephthalate).

[0043] Specifically, the polyester resin (A) can be produced, for example, as follows: For example, an alcohol component containing ethylene glycol and a carboxylic acid component containing terephthalic acid are subjected to a polycondensation reaction in an inert gas (such as nitrogen gas) atmosphere at a reaction temperature of preferably 150 to 280°C, more preferably 160 to 250°C, and even more preferably 170 to 235°C. By adding a barium-containing compound during this reaction, a barium-containing polyester resin (A) can be obtained. Examples of barium-containing compounds include barium titanate, barium carbonate, barium bicarbonate, barium chloride, barium sulfate, barium oxide, barium phosphate, barium hydroxide, barium hydride, barium acetate, barium aliphatic carboxylates, and barium aromatic carboxylates. If necessary, a calcium-containing compound can be added during this reaction to obtain a calcium-containing polyester resin (A). Examples of calcium-containing compounds include calcium carbonate, calcium bicarbonate, calcium chloride, calcium sulfate, calcium oxide, calcium phosphate, calcium hydroxide, calcium hydride, calcium acetate, calcium aliphatic carboxylates, and calcium aromatic carboxylates. If necessary, a phosphorus-containing compound can be added during this reaction to obtain a phosphorus-containing polyester resin (A). The phosphorus-containing compound is not particularly limited as long as it contains phosphorus, and examples thereof include phosphoric acid, phosphates, tris(2,4-di-tert-butylphenyl)phosphite, tris(nonylphenyl)phosphite, cyclic neopentanetetraylbis(2,6-di-t-butyl-4-methylphenyl)phosphite, cyclic neopentanetetraylbis(octadecylphosphite), 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite, tetraalkyl(C12-15)-4,4'-isopropylidenediphenyldiphosphite, diphenyl(2-ethylhexyl)phosphite, triisodecylphosphite, and triphenylphosphite.

[0044] In order to ensure that the polycondensation reaction is carried out, the reaction time is preferably 30 minutes or more, more preferably 2 to 40 hours. It is also effective to reduce the pressure in order to improve the reaction rate at the end of the reaction. The polyester resin (A) is preferably polycondensed in a state containing a barium element, which improves the durability of the toner and provides a wide fixing width. This is presumably because the inclusion of a barium element reduces the amount of cyclic polyester compounds produced as by-products during the polyesterification reaction, resulting in a reduction in the amount of cyclic polyester compounds in the toner. Furthermore, by using a polyester resin synthesized in a state containing calcium element, the amount of cyclic polyester compounds in the toner is reduced, and the durability of the toner can be improved by reducing the amount of cyclic polyester compounds in the toner. Furthermore, by polycondensing the polyester resin (A) in a state where it further contains calcium element, the durability of the toner can be further improved and a wider fixing width can be achieved. This is presumably because the inclusion of calcium element further reduces the amount of cyclic polyester compounds produced as by-products during the polyesterification reaction, resulting in a further reduction in the amount of cyclic polyester compounds in the toner. Furthermore, by using a polyester resin synthesized in a state containing phosphorus, the amount of thermal decomposition products can be reduced, and the toner charge retention rate can be improved, which is preferable.

[0045] During this reaction, a polyol component other than ethylene glycol and a (poly)carboxylic acid component other than terephthalic acid may be added. As mentioned above, PET may be mixed in place of or together with terephthalic acid.

[0046] In this case, an esterification catalyst can be used as needed. Examples of esterification catalysts include tin-containing catalysts (e.g., dibutyltin oxide), antimony trioxide, titanium-containing catalysts (e.g., titanium alkoxides (tetrabutoxytitanate), potassium oxalate titanate, titanium terephthalate, titanium terephthalate alkoxides, catalysts described in JP 2006-243715 A (titanium diisopropoxybis(triethanolaminate), titanium dihydroxybis(triethanolaminate), titanium monohydroxytris(triethanolaminate), titanyl bis(triethanolaminate) and their intramolecular polycondensates, etc.), and catalysts described in JP 2007-11307 A (titanium tributoxyterephthalate, titanium triisopropoxyterephthalate, titanium diisopropoxyditerephthalate, etc.), zirconium-containing catalysts (e.g., zirconyl acetate), and zinc acetate. Among these, titanium-containing catalysts are preferred.

[0047] A stabilizer may be added to the polyester to ensure stable polymerization. Examples of the stabilizer include hydroquinone, methylhydroquinone, and hindered phenol compounds.

[0048] The toner binder of the present invention may contain, in addition to the polyester resin (A), a polyester resin (B) other than the polyester resin (A), a vinyl resin, an epoxy resin, a polyurethane resin, a polycarbonate resin, and the like, and these resins may be amorphous or crystalline resins.

[0049] When the toner binder of the present invention contains a resin other than the polyester resin (A), the weight ratio of the polyester resin (A) is preferably 20% by weight or more, and more preferably 60% by weight or more, based on the weight of the toner binder (100% by weight), from the viewpoint of the fixing width of the toner. Furthermore, based on the weight of the toner binder (100% by weight), the weight ratio of resins other than the polyester resin (A) is preferably 80% by weight or less, and more preferably 40% by weight or less, from the viewpoint of the fixing width of the toner.

[0050] The toner binder of the present invention may contain one or more types of polyester resin (A), and may also contain one or more types of resin other than the polyester resin (A).

[0051] The toner binder of the present invention contains barium element in the range of 10 to 1500 ppm, preferably 30 to 500 ppm, and more preferably 50 to 200 ppm, from the viewpoint of achieving both durability and fixing width of the toner, as measured by fluorescent X-rays. The barium element contained in the toner binder can be quantitatively determined by fluorescent X-ray analysis using the method described above. If the content of barium element contained in the toner binder is less than 10 ppm, the effect of improving the durability of the toner is insufficient, and if it exceeds 1500 ppm, the fixing width deteriorates. The toner binder of the present invention preferably contains calcium element in the range of 20 to 3000 ppm in terms of achieving both durability and fixing width of the toner as measured by fluorescent X-rays. The amount of calcium contained in the toner binder can be determined by fluorescent X-ray analysis using the method described above. The toner binder of the present invention preferably contains phosphorus element in the range of 2 to 500 ppm in terms of chargeability (charge retention rate) measured by fluorescent X-rays. The phosphorus element contained in the toner binder can be quantitatively determined by fluorescent X-ray analysis using the method described above.

[0052] The toner of the present invention comprises the toner binder of the present invention. In addition to the toner binder of the present invention, the toner may contain, if necessary, one or more known additives selected from colorants, release agents, charge control agents, fluidizing agents, and the like.

[0053] As the colorant, any dye or pigment used as a toner colorant can be used. Examples include carbon black, iron black, Sudan Black SM, Fast Yellow G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgasin Red, paranitroaniline red, toluidine red, Carmine FB, Pigment Orange R, Lake Red 2G, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green, Phthalocyanine Green, Oil Yellow GG, Kayaset YG, Orazol Brown B, and Oil Pink OP. The colorant may be any one of these alone or a mixture of two or more. If necessary, magnetic powder (powder of ferromagnetic metals such as iron, cobalt, or nickel, or compounds such as magnetite, hematite, or ferrite) can be added to function as a colorant. The content of the colorant is preferably 1 to 40 parts by weight, more preferably 3 to 10 parts by weight, based on 100 parts by weight of the toner binder of the present invention. When a magnetic powder is used, the content is preferably 20 to 150 parts by weight, more preferably 40 to 120 parts by weight, based on 100 parts by weight of the toner binder.

[0054] Examples of the release agent include aliphatic hydrocarbon waxes such as low molecular weight polypropylene, low molecular weight polyethylene, low molecular weight polypropylene / polyethylene copolymer, polyolefin wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxides thereof; carnauba wax, montan wax, sazol wax, and deacidified waxes thereof; ester waxes such as fatty acid ester wax; fatty acid amides; fatty acids; higher alcohols; fatty acid metal salts; and mixtures thereof.

[0055] Examples of polyolefin waxes include (co)polymers of olefins (such as ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-dodecene, 1-octadecene, and mixtures thereof) [including those obtained by (co)polymerization and thermally degradable polyolefins], oxides of olefin (co)polymers with oxygen and / or ozone, maleic acid modified olefin (co)polymers [for example, modified products of maleic acid and its derivatives (maleic anhydride, monomethyl maleate, monobutyl maleate, dimethyl maleate, etc.)], copolymers of olefins and unsaturated carboxylic acids [(meth)acrylic acid, itaconic acid, maleic anhydride, etc.] and / or unsaturated carboxylic acid alkyl esters [(meth)acrylic acid alkyl (C1 to C18) esters and alkyl maleates (C1 to C18) esters, etc.], and Sasol wax.

[0056] The higher alcohols include aliphatic alcohols having 30 to 50 carbon atoms, such as triacontanol, and the fatty acids include aliphatic alcohols having 30 to 50 carbon atoms, such as triacontanol.

[0057] Examples of the charge control agent include nigrosine dyes, triphenylmethane dyes containing a tertiary amine as a side chain, quaternary ammonium salts, polyamine resins, imidazole derivatives, polymers containing a quaternary ammonium base, metal-containing azo dyes, copper phthalocyanine dyes, metal salicylate salts, boron complexes of benzilic acid, sulfonic acid group-containing polymers, fluorine-containing polymers, and halogen-substituted aromatic ring-containing polymers. Specific examples of charge control agents include T-77 (azo-iron complex manufactured by Hodogaya Chemical Co., Ltd.).

[0058] Examples of the fluidizing agent include colloidal silica, alumina powder, and titanium oxide powder.

[0059] The content of the toner binder in the toner is preferably 30 to 97% by weight, more preferably 40 to 95% by weight, and even more preferably 45 to 92% by weight, based on the weight of the toner. The content of the colorant is preferably 0.05 to 60% by weight, more preferably 0.1 to 55% by weight, and even more preferably 0.5 to 50% by weight, based on the weight of the toner. The content of the release agent is preferably 0 to 30% by weight, more preferably 0.5 to 20% by weight, and even more preferably 1 to 10% by weight, based on the weight of the toner. The content of the charge control agent is preferably 0 to 20% by weight, more preferably 0.1 to 10% by weight, and even more preferably 0.5 to 7.5% by weight, based on the weight of the toner. The content of the fluidizing agent is preferably 0 to 10% by weight, more preferably 0 to 5% by weight, and even more preferably 0.1 to 4% by weight, based on the weight of the toner. The total content of the additives is preferably 3 to 70% by weight, more preferably 5 to 60% by weight, and even more preferably 8 to 55% by weight, based on the toner weight. By setting the composition ratio of the toner within the above range, it is possible to easily obtain a toner that has good low-temperature fixability, hot offset resistance, chargeability (charge retention rate), durability of print quality, and toner durability.

[0060] The toner preferably contains barium element in the range of 10 to 1500 ppm as measured by fluorescent X-rays. When the toner contains barium element in the range of 10 to 1500 ppm, the toner can be excellent in durability and fixing width. The toner preferably contains calcium element in the range of 20 to 3000 ppm as measured by fluorescent X-rays. When the toner contains calcium element in the range of 20 to 3000 ppm, the toner can be excellent in durability and fixing width. The amount of calcium contained in the toner can be determined by fluorescent X-ray analysis using the method described above. The toner preferably contains phosphorus element in the range of 2 to 500 ppm as measured by fluorescent X-rays. When the toner contains phosphorus in the range of 2 to 500 ppm, the toner can have excellent charging properties. The phosphorus element contained in the toner can be quantitatively determined by fluorescent X-ray analysis using the method described above.

[0061] The toner may be obtained by any of known methods such as a kneading and pulverizing method, an emulsion phase inversion method, and a polymerization method. For example, when a toner is obtained by a kneading and pulverizing method, the components constituting the toner except for the fluidizing agent are dry-blended, melt-kneaded, then coarsely pulverized, and finally, the toner is pulverized using a jet mill pulverizer or the like, and further classified to obtain fine particles having a volume average particle size (D50) of preferably 5 to 20 μm, and then the fluidizing agent is mixed therein to produce the toner. The volume average particle size (D50) is measured using a Coulter counter (for example, Multisizer III (trade name, manufactured by Beckman Coulter, Inc.)).

[0062] In addition, when a toner is obtained by an emulsion phase inversion method, the components constituting the toner except for the fluidizing agent are dissolved or dispersed in an organic solvent, and then emulsified by adding water, etc., and if necessary, the resulting emulsion is subjected to aggregation, etc., and then separated and classified to produce the toner. The volume average particle size of the toner is preferably 3 to 15 μm.

[0063] The toner is mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite, magnetite, and ferrite coated with resin (acrylic resin, silicone resin, etc.) as needed to be used as a developer for the electric latent image. When carrier particles are used, the weight ratio of the toner to the carrier particles is preferably 1 / 99 to 99 / 1. Alternatively, the toner can be rubbed against a member such as a charging blade instead of the carrier particles to form an electric latent image. The toner does not necessarily contain carrier particles.

[0064] The toner is fixed to a support (paper, polyester film, etc.) by a copier, printer, etc. to form a recording material. As a method for fixing to a support, known methods such as a heat roll fixing method and a flash fixing method can be used.

[0065] The toner and the toner binder of the present invention are used for developing electrostatic images or magnetic latent images in electrophotography, electrostatic recording, electrostatic printing, etc. More specifically, they are used for developing electrostatic images or magnetic latent images particularly suitable for full color applications.

[0066] The present specification discloses the following:

[0067] The present disclosure (1) is a toner binder containing a polyester resin obtained by polycondensing an alcohol component and a carboxylic acid component, wherein the polyester resin is a polyester resin (A) in which the alcohol component contains ethylene glycol and the carboxylic acid component contains terephthalic acid, and the toner binder is characterized in that it contains barium element in a range of 10 to 1500 ppm when measured by fluorescent X-ray.

[0068] The present disclosure (2) is the toner binder according to the present disclosure (1), which contains calcium element in the range of 20 to 3000 ppm as measured by fluorescent X-rays.

[0069] The present disclosure (3) is the toner binder according to the present disclosure (1) or (2), which contains phosphorus element in the range of 2 to 500 ppm as measured by fluorescent X-rays.

[0070] The present disclosure (4) is the toner binder according to any one of the present disclosures (1) to (3), wherein the alcohol component of the polyester resin further contains an alkylene oxide adduct of bisphenol A.

[0071] The present disclosure (5) is a toner containing the toner binder according to any one of the present disclosures (1) to (4). [Example]

[0072] The present invention will be further explained below with reference to examples and comparative examples, but the present invention is not limited to these. In the following, Examples 1 to 3, 5, 8 to 10 and 12 refer to Reference Examples 1 to 8.

[0073] Example 1: Synthesis of toner binder (TB1) A reaction vessel was charged with 73 parts by weight of ethylene glycol, 15 parts by weight of trimethylolpropane, 204 parts by weight of bisphenol A·PO 2-mol adduct, 365 parts by weight of bisphenol A·PO 3-mol adduct, 435 parts by weight of terephthalic acid, 0.213 parts by weight of barium titanate as an additive, and 1 part by weight of tetrabutoxy titanate as a condensation catalyst. The mixture was reacted at 220°C under a nitrogen stream for 5 hours while distilling off the resulting water and ethylene glycol. The reaction was then continued under reduced pressure of 0.5 to 2.5 kPa. When the acid value reached 2 mg KOH / g or less, the mixture was cooled to 175°C and discharged. The distillate recovered by distillation was 94 parts by weight of water and 11 parts by weight of ethylene glycol. The resulting resin was cooled to room temperature, pulverized, and granulated to obtain a toner binder (TB1) containing polyester resin (A1). The toner binder (TB1) had a Tg of 61° C. and a weight average molecular weight of 40000. The physical properties of the toner binder (TB1) are shown in Table 1. In Table 1, ND indicates that it was not detected.

[0074] <Examples 2 to 4> Synthesis of toner binders (TB2) to (TB4) Toner binders (TB2) to (TB4) containing polyester resins (A2) to (A4) were produced in the same manner as the toner binder (TB1) of Example 1, except that the additives were changed to the compositions and parts by weight shown in Table 1. The physical properties of each toner binder are shown in Table 1.

[0075] Example 5: Synthesis of toner binder (TB5) A reaction vessel was charged with 731 parts by weight of PET flakes (commercially available PET bottles cut into 1 cm cubes), 578 parts by weight of propylene glycol, 0.017 parts by weight of barium titanate as additives, 7,500 parts by weight of calcium carbonate, 0.063 parts by weight of phosphoric acid, and 1 part by weight of tetrabutoxy titanate as catalyst, and the mixture was reacted at 220°C in a sealed container for 5 hours to produce a homogeneous viscous liquid. Next, 16 parts by weight of glycerin, 103 parts by weight of bisphenol A·PO 2-mol adduct, and 170 parts by weight of bisphenol A·PO 3-mol adduct were added to the reaction vessel. The reaction was continued for 5 hours under a nitrogen stream at 220°C while distilling off ethylene glycol and propylene glycol. The reaction was then continued under reduced pressure of 0.5 to 2.5 kPa. When the acid value reached 2 mg KOH / g or less, the mixture was cooled to 175°C and discharged. The distillate recovered by distillation was 164 parts by weight of ethylene glycol and 434 parts by weight of propylene glycol. The resulting resin was cooled to room temperature, then pulverized and granulated to obtain a toner binder (TB5) containing a polyester resin (A5). The physical properties of the toner binder (TB5) are shown in Table 1.

[0076] Example 6: Synthesis of toner binder (TB6) A reaction vessel was charged with 492 parts by weight of PET flakes (commercially available PET bottles cut into 1 cm cubes), 318 parts by weight of ethylene glycol, 0.213 parts by weight of barium titanate as additives, 0.563 parts by weight of calcium carbonate, 0.063 parts by weight of phosphoric acid, and 1 part by weight of tetrabutoxy titanate as catalyst, and the mixture was reacted at 220°C in a sealed container for 5 hours to produce a homogeneous viscous liquid. Next, 16 parts by weight of trimethylolpropane, 239 parts by weight of bisphenol A·PO 2-mol adduct, 334 parts by weight of bisphenol A·PO 3-mol adduct, and 7 parts by weight of succinic acid were added to the reaction vessel. The mixture was reacted at 220°C under a nitrogen stream for 5 hours, while the resulting water and ethylene glycol were distilled off. The reaction was then continued under reduced pressure of 0.5 to 2.5 kPa. When the acid value reached 2 mg KOH / g or less, the mixture was cooled to 175°C and discharged. The distillate recovered by distillation was 2 parts by weight of water and 406 parts by weight of ethylene glycol. The resulting resin was cooled to room temperature, then pulverized and granulated to obtain a toner binder (TB6) containing a polyester resin (A6). The physical properties of the toner binder (TB6) are shown in Table 1.

[0077] Example 7: Synthesis of toner binder (TB7) A reaction vessel was charged with 407 parts by weight of PET flakes (commercially available PET bottles cut into 1 cm cubes), 113 parts by weight of propylene glycol, 123 parts by weight of neopentyl glycol, 16 parts by weight of trimethylolpropane, 433 parts by weight of isophthalic acid, 2.501 parts by weight of barium titanate as additives, 0.050 parts by weight of calcium carbonate, 1.531 parts by weight of phosphoric acid, and 1 part by weight of tetrabutoxy titanate as catalyst. The mixture was reacted at 200 °C under a nitrogen stream for 15 hours while distilling off the resulting water, propylene glycol, and ethylene glycol. The mixture was then reacted under a reduced pressure of 2.5 to 5.0 kPa. When the acid value reached 2 mg KOH / g or less, the mixture was cooled to 175 °C and discharged. The distillate recovered by distillation was 94 parts by weight of water, 7 parts by weight of propylene glycol, and 6 parts by weight of ethylene glycol. The resulting resin was cooled to room temperature, then pulverized and granulated to obtain a toner binder (TB7) containing a polyester resin (A7). The physical properties of the toner binder (TB7) are shown in Table 1.

[0078] Comparative Examples 1 and 2: Synthesis of Toner Binders (RTB1) to (RTB2) Toner binders (RTB1) to (RTB2) containing polyester resins (RA1) to (RA2) were obtained in the same manner as in the production method of the toner binder (TB1) of Example 1, except that no additives were added. Table 1 shows the physical properties of the toner binders (RTB1) to (RTB2).

[0079] <Comparative Example 3> A toner binder (RTB3) containing a polyester resin (RA3) was obtained in the same manner as in the production method of the toner binder (TB1) of Example 1, except that the additives were changed to the compositions and parts by weight shown in Table 1. The physical properties of the toner binder (RTB3) are shown in Table 1.

[0080] [Table 1]

[0081] Example 8 A toner (TC1) of the present invention was obtained by the following method.

[0082] The toner binder (TB1), colorant, release agent, and charge control agent were premixed using a Henschel mixer (FM10B, manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and then kneaded in a twin-screw kneader (PCM-30, manufactured by Ikegai Corporation). The mixture was then finely pulverized using a supersonic jet mill, Labojet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain toner particles with a particle size D50 of 7 μm. Next, 100 parts by weight of the toner particles were mixed with 0.5 parts by weight of colloidal silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) using a sample mill to obtain a toner (TC1) of the present invention. The physical properties and evaluation results of the toner (TC1) are shown in Table 2. In Table 2, ND indicates that the toner was not detected.

[0083] The colorants, release agents, and charge control agents in Table 2 are as follows: Colorant: Carbon black MA-100 [Mitsubishi Chemical Corporation] Release agent: Carnauba wax [Toyo Adle Co., Ltd.] Charge control agent: T-77 [Hodogaya Chemical]

[0084] [Evaluation method] [1] Low-temperature fixability Using the above toner, an unfixed image was developed using a commercially available copier [AR5030; manufactured by Sharp Corporation] and evaluated using the fixing unit of the commercially available copier [AR5030; manufactured by Sharp Corporation]. The fixed image was rubbed with a pad, and the fixing roll temperature at which the remaining image density measured using a Macbeth reflection densitometer RD-191 [manufactured by Macbeth Corporation] was 75% or more was defined as the minimum fixing temperature (MFT) (°C). A lower MFT indicates better low-temperature fixing ability. Table 2 shows the MFT as low temperature fixability (°C).

[0085] [2] Hot offset resistance The presence or absence of hot offset in the fixed image was visually evaluated in the same manner as in the above-mentioned low-temperature fixability evaluation method. The fixing roll temperature at which hot offset occurred was defined as the hot offset occurrence temperature (HOT) (°C). A higher HOT indicates better hot offset resistance. In Table 2, HOT is shown as hot offset resistance (°C).

[0086] [3] Fixing width The value obtained by subtracting the MFT from the HOT is the fixing width (°C) and is shown in Table 2. A larger fixing width means a better balance between low temperature fixability and hot offset resistance.

[0087] [4] Chargeability (charge retention rate) (1) 1 g of toner and 0.01 g of Aerosil R8200 (manufactured by Evonik Japan Co., Ltd.) were mixed for 1 hour in a shaker. 0.5 g of this mixture and 20 g of ferrite carrier (F-150, manufactured by Powder Tech Co., Ltd.) were placed in a 50 mL glass bottle, and the bottle was conditioned at 25°C and 50% relative humidity for 8 hours (referred to as low-temperature, low-humidity conditions). (2) The mixture was agitated by friction at 50 rpm for 10 minutes and 60 minutes using a Turbula shaker mixer, and the amount of charge after each time was measured using a blow-off charge amount measuring device (manufactured by Kyocera Chemical Corporation). Using the obtained values, "charge amount after 60 minutes of friction / charge amount after 10 minutes of friction" was calculated, and this was taken as the charge stability index. A larger charge stability index indicates a better charge retention rate. Under these evaluation conditions, a charge stability index of 0.8 or more is preferred. Table 2 shows the charge stability index as a charge retention rate.

[0088] [5] Durability Using a commercially available copier [MX-M754FN, manufactured by Sharp Corporation], the toner was removed, the carrier and toner were separated, and the inside of the cartridge was cleaned with an air blower. The prepared toner and carrier were then mixed and conditioned for 14 days at 40°C and 50% relative humidity. This allowed for evaluation of durability under more severe conditions. Using this as a two-component developer, continuous copies were made at a printing speed of 75 pages per minute. The print quality was checked for 2,000, 6,000, and 10,000 pages, and a portion of the toner was sampled to measure particle size. Durability was evaluated according to the following criteria. The volume average particle size (D50) was measured using a Coulter counter (trade name: Multisizer III [manufactured by Beckman Coulter, Inc.]). The results are shown in Table 2. [Judgment criteria] <Print quality> ◎: No change in image quality and no fogging even after 10,000 copies. ○: Fog occurs after 10,000 copies. △: Fog occurs after 6,000 copies. ×: Fog occurs after 2,000 copies. <Toner status> ◎: The change in particle size D50 is less than 3%, and no fine powder of 2 μm or less is observed. ○: The change in particle size D50 is 3% or more and less than 4%, and no fine powder of 2 μm or less is observed. △: The change in particle size D50 is 4 to 5%, and no fine powder of 2 μm or less is observed. ×: The change in particle size D50 exceeds 5%, or fine powder of 2 μm or less is generated. Under these evaluation conditions, it is preferable that both the print quality and the toner condition are in the range of ◯ or ⊚.

[0089] <Examples 9 to 16 and Comparative Examples 4 to 6> As in Example 8, toners (TC2) to (TC9) and (RTC1) to (RTC3) were obtained by blending according to the blending ratios shown in Table 2. The physical properties and evaluation results of toners (TC2) to (TC9) and (RTC1) to (RTC3) are shown in Table 2.

[0090] [Table 2]

[0091] All of the toners containing the toner binders of the examples were excellent in durability, chargeability, and fixation width. Furthermore, the toners of the examples in which the phosphorus content in the toner binder was in the range of 2 to 500 ppm were even more excellent in chargeability. On the other hand, the toner containing the toner binder of the comparative example was inferior in at least durability and fixation width. [Industrial Applicability]

[0092] The toner containing the toner binder of the present invention has excellent durability, chargeability and a wide fixing width, and therefore can be suitably used as a toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing and the like.

Claims

1. A toner binder comprising a polyester resin obtained by polycondensing an alcohol component and a carboxylic acid component, wherein the polyester resin is a polyester resin (A) in which the alcohol component contains ethylene glycol and trimethylolpropane, and the carboxylic acid component contains terephthalic acid, and the toner binder is characterized in that the polyester resin contains barium element in a range of 10 to 1500 ppm, calcium element in a range of 20 to 3000 ppm, and phosphorus element in a range of 2 to 500 ppm, as measured by fluorescent X-rays.

2. 2. The toner binder according to claim 1, wherein the alcohol component of the polyester resin further contains an alkylene oxide adduct of bisphenol A.

3. A toner comprising the toner binder of claim 1.

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